Surface outlet



June 23,1959 G AND R 2,892,174

SURFACE OUTLET Filed Feb. 26, 1957 [/7V6f7 far G'eor 9 B. Banana gr Unit States. Pa e The present invention relates to' an electrical outlet and particularly one which is connected to a two 'co nductor wife by piercing the insulation of the wire. Such outlets are commonly called surface outlets since they are mainly used as part of an extension cord and are fastened to the baseboard of a wall by means of a wood ice with the two-conductor wire in place the back cover plate removed to show how the insulation has been flattened out to form the strain relief means,

Referring in detail to the drawing and in particulaf to Figure 6, the insulating housing for the outlet cemprises a recessed base 10 of generally cup-shape with a convex top surface 11, generally parallel side walls 12 and end walls 13. The back face 14 opposite the front face 11 is open until the back cover plate 15 of irisii; lating' material is assembled to the base 10. The currentcarrying elements of this outlet are represented by a pair of contact strips 16 of thin bronze material which are arranged in a parallel manner within the base 10. A central post 17 is formed in the base with a throughopening 18 for receiving a fastening screw 19 as shown in Figure 5. The screw extends from the front face of the 'base 10 completely through the housing and out screw. Surface outlets with insulationpiercingmeans are old in this art as is shown in No. 2,316,167. I l

The principal object of this inventionis to provide an electrical-"outlet having insulation piercing means for making connection with a pair of insulated conductors, and of providing a novel strainrelief for the conductors. A further object of this invention is to provide an improved electrical outlet having an insulation piercing feature, where the back cover is designed to force the conductor insulation into a shape which will prevent the outlet from becoming disengaged from atwoconductor wire. i My invention has an insulating housing. with a recessed base and a 'cover member. The base has. oneopen wall that is closed by the cover member when a fastening screw is forced through both the base andthe cover and threaded into a supporting surface. There are two contact strips located in the housing, each strip having a prong that will ierce 011.6 of the insulated conductors the Huppert: Patent through a small aperture 20 in the back cover 15. This screw 19 represents the only means for holding the cover 15 on the base 10, Le, by sandwiching the cover between the base and a supporting surface once the screw is threaded into place.

. parallel files that extend longitudinally of the base. The

when the cover plate is pressed tight against the base.

It; is desirable to provide suchv a device with a strain relief means to prevent the wire from being pulled loose from the outlet. My invention, includes the combination of; a, pair of transverse partitions located in the. base with notches for supporting the two insulated conductors over the contact strips. The back cover is provided with a pair of bosses which are located over the prongs of the contact strips, and force the insulated conductors onto the prongs as well as flatten out the insulation in the area between the two partitions. Hence, any pulling force exerted on the two-conductor wire will be resisted by the flattened portion of the insulated conductors which cannot slip through the notches in the partitions.

My invention will be better understood from the following description taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

Figure 1 is a top plan view of a triple surface outlet embodying my invention.

Figure 2 is a right side view of the outlet of Figure 1.

Figure 3 is a view similar to that of Figure 2 except that it is a cross-sectional view taken on the lines 3--3 of Figure 1.

Figure 4 is a bottom plan view of my invention with the cover plate removed.

Figure 5 is a transverse cross-sectional view taken on the lines 5-5 of Figure 1.

Figure 6 is an exploded isometric view showing the details of construction of my invention.

Figure 7 is a bottom plan view similar to Figure 4 purpose of the rounded or convex front face 11 will be understood ,by studying the side view of Figure 2. The two outermost pairs of openings 21 have anaxis of penetration which is substantially at an angle of 45 degrees with the similar axis of the central pair of openings 21. Hence, there is less likelihood that the attachment plugs will interfere with each other when there are three plugs attached to the outlet at the same time.

Comparing Figures 3 and 6, the nature of the contact strips 16 will be discussed in detail. Since the contact strips 16 are identical, reference will be made to only one of them. The longitudinal edge of each strip nearest the openings 21 is provided with three spring fingers; namely, the central finger 22 and the two outermost fingers 23. The central finger 22 is bent slightly inwardly of 'the base while the outermost fingers 23 are formed outwardly toward the side walls 12' of the base. Accordingly, the attachment plugs, when they are assembled in the outlet, tend' to force the endsof the contact strips away from each other and to draw the central portion of the strips toward each other as will be well understood by those skilled in this art.

Looking at the bottom plan view of the base 10 in Figure 4, the parallel nature of the two contact strips 16 becomes immediately apparent. These strips 16 are not only parallel, they underlie the openings 21 in the front face 11 of the base. The end walls 13 are each provided with a two-conductor wire-receiving opening 25 so that the cover plate 15 will completely close the open back wall 14 of the base, and provide a completely enclosed housing for the outlet. As shown in Figures 3, 4 and 6, the back edge 26 of each contact strip 16 is provided with a pair of prongs 27 which are to pierce the insulated conductor of a two-conductor wire 28 shown in Figure 7. The wire 28 is commonly described in the industry as a rip-cord since it has a ripping groove 29 on its top and bottom sides between the conductors. The wire is separated within the outlet as shown in Figure 7 so that each insulated conductor will overlie one of the contact strips 16 in the central area thereof, and specifically where the prongs 27 are located. Figure 4 shows a pair of transverse partitions 30 on opposite sides of the central post 17 to serve as a supporting means for the mid-portion of the contacts 16. Each partition 30 has a notch 31 where the contacts intersect the partitions so that the insulated conductors may be fitted into these notches and held in place over the prongs 27.

The back cover plate 15 has been provided witha pair of similar embossings 32 which project inwardly of the housing and overlie the prongs 27 of the contact strips, as is best shown in Figure 5. Since the insulated conductors are not confined along their sides they tend to flatten out and bulge outwardly at the sides as at 33 in the area between the two transverse partitions 30. As a consequence, due to the rigidity of the insulating material on the conductors, the bulged portions 33 serve as a strain relief and cannot be pulled through the notches 31 of the partitions which might disconnect the contact strips 16 from the conductors.

Having described above my invention of an electrical outlet having contacts which pierce the insulated conductors it will be appreciated that I have provided a novel strain relief means by taking advantage of embossings on the back cover of the outlet. This is possible because the insulated conductors are not confined in the area between the two transverse partitions but are merely held by the notches in the partitions.

Modifications of this invention will occur to those skilled in this art, and it is to be understood, therefore, that this invention is not limited to the particular embodiment disclosed but that it is intended to cover all modifications which are within the true spirit and scope of this invention.

.What I claim as new and desire to secure by Letters Patent of the United States is: g 1. An electrical outlet comprising a housing with a recessed base and a flat cover plate for closing one 'open wall of the base, a pair of parallel contact strips mounted longitudinally and edgewise in the base, and a series of attachment plug-receiving openings in the wall of the base that is opposite the said open Wall for gaining access to the said contact strips, the edge of both strips that is nearest the cover having at least two prongs facing the cover, there being a two-conductor wire? receiving opening in at least one end of the base adjacent the ends of the contact strips, and a pair of transverse partitions in the base, the partitions being slotted to a pair of inwardly facing bosses, each boss being disposed over one of the contact strips and centered between the two prongs of a singlecontact strip so as to press the insulated conductors over the prongs and cause them to become impaled on the prongs of the contact strips and flatten out the insulation to serve as a strain relief, so that the conductors may not be pulled through the notches of the partitions.

2. An electrical outlet as recited in claim 1 wherein the two-conductor wire is separated within the housing into two single insulated conductors which are disposed in the notches of the partitions to overlie the prongs of the contact strips, there being a fastening screw extending through the wall containing the attachment plugreceiving openings and through the cover plate for fastening the outlet to a supporting surface and forcing the base tightly against the flat cover plate, whereby portions of the conductors will be compressed betweenthe prongs 0f the contact strips and the bosses of the cover plate upon the tightening of the screw.

3. An electrical outlet having an insulating housing with a recessed base and a removable cover member for enclosing a pair of metal contact strips, the invention comprising a'meansto connect one conductor of atwoconductor insulated wire to each contact, the contacts being arranged edgewise in the housing and having at least two prongs on the edge nearest the cover so that the cover will force each insulated conductor to become impaled on the prongs, the sides of the conductors being unconfined, there being a transverse partition in the base on opposite sides of the prongs of the contacts, the partitions being slotted to receive the contact strips therethrough, each partition having open notches for closely receiving the insulated conductors, the cover member having a pair of inwardly facing convex embossings each embossing being centered between the two prongs of a contact strip to press against the conductors and flatten out the insulation to form bulges in the sides that will not slip through the notches of the partitions.

References Cited in the file of this patent UNITED STATES PATENTS Eby Dec. 23, 1941 2,751,568 Despard June 19,- 

